That's not at all how it works. One doesn't get that body type from running long distances, one runs long distances well because they are predisposed to that body type.

Consider, for example, a swim meet. If you look at the competitors in prelims, you'll see a variety of body types. By the semifinals, you'll see a smaller variety, and by the finals, you'll likely see a field of competitors with similar builds. Most look at that and assume a build like that of those in the finals is the result of an intense swimming regiment, when actually it's that body type that enabled swimming success. The entire field of competitors may have put in similar levels of effort, but the physiological advantages genetically granted to the better swimmers is what resulted in their relative success.

Distance running has no effect on ones weight...are you really saying that?

Exercise can change your physique dramatically. I've been a state-level bicycle racer (170 lb and skinny), master swimmer (195 lb brick shithouse), triathlete, road runner for decades.

Different distances lead to leaner or stockier builds.

The vast majority of the top runners in the Olympic and other world-class marathons are well under 6 feet tall, with most closer to 5 feet tall. Sprinters, on the other hand, are well over 6 feet. Are you suggesting distance running makes people shorter?

That is not the truth. While generally not over 6 feet tall, the Olympic distance runners had a very normal height distribution. One of the shorter, Hillary Bor, is still 5' 7".

Olympics aren't a great test for this. Look at top marathon runners size over time.

http://www.runnersworld.com/sweat-science/the-incredible-shr...

That kinda says what I'm saying, top marathoners/distance runners are of average height (around 5'7").

Average height for Japan, maybe, but not really anywhere in the Western world. Average height in the Netherlands is over 6 feet, for example.

Still not closer to 5 foot tall. I don't know how or why this is still an argument. Marathon runners are not 5' tall. That's tiny. And average height in the Netherlands is right at 6'.

Netherlands is an extreme outlier (world's tallest people). 5 foot 7 is actually standard in my country and even on the tall side for my continent, South America (although better diet is fixing that). It's also tall for Asia and Africa.

https://en.wikipedia.org/wiki/List_of_average_human_height_w...

Eliud Kipchoge, winner of the gold medal in Rio, is 5'5.5". That's closer to 5 feet than it is to 6.

Yep, and the other two guys were both over 5'8". Actually, out of every distance event, 2/3 of the medal winners were over 5'8".

Feyisa Lilesa is 5'9" Galen Rupp is 5'11" Mo Farah is 5'9" Bernard Lagat is 5'8" Matt Centrowitz is 5'9" Paul Chelimo is 5'11" Tamirat Tola is 5'11" Taoufik Makhloufi is 5'9" Nick Willis is 6' Evan Jager is 6'2" Mahiedine Mekhissi-Benabbad is 6'3"

It doesn't have any effect on your bone structure. Competitive long distance runners are built like chickens.

This is pretty far off. I'm 6'4" and weighed 165 when I ran cross country competitively. I didn't look like the type of runner you're describing, neither did 90% of my teammates. Running more than a mile at a time won't turn you into a stick thin marathoner. Olympians are hardly what people should be comparing themselves to if they're looking to get into running.

6'4" and 165lbs (193cm/74.8kg) seems quite thin though - I don't think you are necessarily providing the counterexample you think you are here? Maybe I'm misunderstanding your point. Internet BMI calculator says that would make you "underweight" and put you in the 7th percentile for your height and weight (as in, 93% of people as tall as you weigh more than you).

I'm not saying I wasn't thin. I definitely was. However, you wouldn't have been able to pick me out from a crowd as a 'cross country runner'. And to be competitive at that level, you can't be carrying around any extra weight. While BMI can be a helpful tool, it's pretty flawed. It doesn't take into account muscle/fat ratio. I really don't have much body fat, but am now only 5 pounds away from being 'overweight' accordingly to BMI.

Really, my point was that running 15-20 miles a week won't give you the body of a Kenyan Olympian. Running can be incredibly rewarding, I was simply trying to state that if I had to run 90 miles a week to be barely underweight, 15 miles a week shouldn't scare anyone off if they're just trying to be healthier.

interesting comment. i wonder though -- how much of this is cause vs effect (e.g., people with bodies naturally suited to shorter vs longer distances), and how much of "do i want to look like that" is your particular, perhaps arbitrary cultural associations of "this is good"?

Sprints/HIIT have been to shown to be more effective at what many people are trying to get out of running - in better shape and body composition changes.

Elite distance runners are smaller on average but they are also pretty damn lean.

Interesting logic. I do want to look like that. How many miles do I have to run until I turn into a 5'6" Kenyan man?

I'm sorry. You're right. Exercise has no effect on muscle mass

Short and mid distance runners spend equal amount of time in a gym doing squads and upper body exercises as they do running, and the diet is completely different between two of them, that is why they have a more muscular look compared to their long distance runners.

Take a look to any popular marathon races and you will discover that most of the participants have a normal athletic physique.